Flaw recognition by target matching method

Based on the maximum output signal-to-noise ratio criterion, we proposed a target-matching method for flaw recognition in ultrasonic testing. The characteristic of a target flaw is used as a prior knowledge. So the output response can be a self-correlative process with the maximum SNR. The new method is verified by a series of experiments for 5 small typical flaws, including the flat-bottom hole, the narrow-slot crack, the ribbon crack, the internal crack, and the side-drilled hole. the results perform much better testing sensitivity than those in the conventional detection.